title: Dextran-coated silica nanoparticles for calcium-sensing.
abstract: This article describes the synthesis and characterisation of fluorescent composite nanoparticles consisting of a silica core and a dextran shell. The silica core contains a rhodamine-based reference dye, which allows ratiometric measurements and the dextran shell is labelled with the Ca(2+)-sensitive dye Fluo-4. The nanoparticles have an average hydrodynamic diameter of 95 nm, good colloidal stability and show a 2.9-fold increase in fluorescence intensity upon binding to Ca(2+) ions. The apparent dissociation constant of K'(d) ≈ 520 nM is well suited for measurements in the physiological range.
authors.affiliation: National Biophotonics and Imaging Platform Ireland (NBIPI), School of Physics, Dublin City University, Dublin, Ireland.
authors.forename: Anja
authors.initials: A
authors.lastname: Schulz
authors.forename: Robert
authors.initials: R
authors.lastname: Woolley
authors.forename: Thibault
authors.initials: T
authors.lastname: Tabarin
authors.forename: Colette
authors.initials: C
authors.lastname: McDonagh
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry; D002118:Calcium / Q000032:analysis*; D003911:Dextrans / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D053758:Nanoparticles / Q000737:chemistry*; D012235:Rhodamines / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014966:Xanthenes / Q000737:chemistry
chemical_list: D000814:Aniline Compounds; D003911:Dextrans; C409648:Fluo 4; D012235:Rhodamines; D014966:Xanthenes; D012822:Silicon Dioxide; D002118:Calcium